Subsurface Exploration for I-40 Reconstruction in the Pigeon River Gorge Post Hurricane Helene-PPT Presentation

PPT Presentation

Pdf Summary

The presentation describes subsurface exploration for reconstructing I-40 through the Pigeon River Gorge after Hurricane Helene. The corridor has a history of recurring closures and repairs, so the project aims to create a resilient, reliable system that can better withstand severe storms.<br /><br />Investigations covered five miles of roadway and were conducted in three phases. More than 600 data points were collected using soil-nail observations, over 15 miles of Multichannel Analysis of Surface Waves (MASW) surveys, air-track probes, conventional borings, rock coring, optical televiewer surveys, and laboratory testing. Findings showed highly variable overburden and a steep, uneven bedrock surface: observed rock depths ranged from 2 to 38 feet in soil nails and 3 to 58 feet in air-track probes. Rock was not encountered in some investigations, underscoring the complexity of the ground conditions.<br /><br />To organize and interpret the large dataset, the team used MORTAR, an internally developed, georeferenced database and visualization platform with QA/QC and linked project information. It supported mapping, data integration, and a more informed design process.<br /><br />Several structural concepts were considered, including a tunnel, viaduct, walls, and buttresses. The presentation identifies some options as no-go concepts and discusses roller-compacted concrete buttresses and pipe-pile walls among the approaches considered.<br /><br />Key lessons include adapting investigation methods to obtain timely information for emergency decisions, matching ground conditions to design concepts, and using centralized data management to review and interpret large volumes of subsurface information.

Keywords

subsurface exploration

I-40 reconstruction

Pigeon River Gorge

Hurricane Helene

MASW surveys

rock coring

bedrock variability

MORTAR database

geotechnical investigation

resilient infrastructure